Venus, Moon and Space Beehive Shine Together Early Wednesday

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The predawn morning sky on Wednesday (Sept. 12) will contain a
beautiful celestial sight that will likely attract a lot of
attention for many early risers.

If you venture outside several hours before sunrise, low above
the east-northeast horizon you'll see a slender sliver of a
waning crescent moon, weather permitting. And located to its left
will be a dazzling, silvery-white "star" shining with a steady
glow.

That will be the planet Venus, shining at an eye-popping
magnitude of - 4.2 (13 times brighter than Sirius, the brightest
star in the night sky) from a distance of 85.6 million miles
(137.7 million kilometers) from Earth.

Venus dominates the heavens from the time it comes up
over the horizon a little north of due east around 3 a.m. local
daylight time; nearly four hours before the sun and some two
hours before the first light of dawn. Its brightness puts
neighboring stars — even its closest rival, Jupiter, which
will be riding about halfway up in the eastern sky — to shame.
[September
2012 Night Sky Guide (Sky Maps)]

So it is that on Wednesday morning, the moon and Venus, the two
brightest objects of the nighttime sky will be separated by about
4 degrees. Your clenched fist held at arm's length measures
roughly 10 degrees, so on Wednesday, moon and planet will be
about a "half fist" apart.

What will make this attractive scene even more attractive will
be "Earthshine," where the unilluminated portion of the
moon will seem to glow dimly with an eerie blue-gray light. First
described by
Leonardo da Vinci in his Codex Leicester, circa
1510, this mysterious glow is caused by sunlight reflected off
the oceans and cloud tops of Earth, directed toward the
moon.

The moon will be only 16-percent illuminated by the sun; a
narrow, yellow-white sliver contrasting with the
blue-gray portion of the rest of the lunar disk
giving it a striking three-dimensional appearance,
especially in binoculars.

And as the morning progresses, the moon and Venus will climb well
up into the eastern sky.

In spite of the fact that Venus was at greatest elongation
(maximum angular separation) from the sun on Aug. 17th, this
dazzling planet appears even higher in the sky during this
month. In fact, Venus is now at the peak of its highest morning
apparition (for skywatchers at midnorthern latitudes) – about
40-degrees ("four fists") high at each September sunrise.

And as a bonus, Venus will also slide 2.5 to 3 degrees south of
the center of the famous Beehive star cluster in Cancer (M44),
from Wednesday through Friday morning (Sept. 14), a very pretty
sight in binoculars. Sunrise or late in morning twilight is
the best time to study Venus in
small telescopes. Telescopically, however, Venus
is now just a tiny, featureless and increasingly gibbous
disk.

By month's end Venus will have descended to within 5 degrees of
Regulus, which it will pass exceedingly close to on
October 3rd. We'll have more to say about that later this
month. Stay tuned!

Editor's note: If you have a photo of the moon, Venus and the
Beehive cluster, or any other amazing night sky photo that you'd
like to share for a possible story or image gallery, please
contact managing editor Tariq Malik at tmalik@space.com.

Joe Rao serves as an instructor and guest lecturer at New
York's Hayden Planetarium. He writes about astronomy for The New
York Times and other publications, and he is also an on-camera
meteorologist for News 12 Westchester, New York.